OK. I have to admit I have no idea how other people are sorting this out.
In 1952 The K model started out with 19 inch wheels. Two years later (1954) it appears they offered the choice of either the 19's or 18 inchers. The 18's actually have a -53 part number.
In 1954 they made longer (or shorter ?) tubes and springs. I have always believed they were 1 inch longer. Damper assemblies also were made to suit with 3 different part numbers.
Fast forward to today and I see new springs being offered for K's and Sportsters. But all the same length – 20 inches.
Now if the tubes vary by 1 inch in length (and the dampers as well) shouldn't the springs ALSO vary in length ?
It might well be possible to compress a longer spring into a shorter tube. But that will effect static ride height. I have to wonder if coil bind might also be an issue.
And a shorter spring in a longer tube would introduce sag.
I believe that the damper rods are shorter or longer to accommodate the changes in spring length.
But I don't think (don't really know here) I've ever noticed damper rods with different lengths.
Why I am asking this is that I'm currently working on a set of forks for my 58 CH project.
It came with a set of assembled forks. But with chromes tubes I knew they weren't original.
Tube with installed damper and spring waiting for retainer.
Length of spring that protrudes from the tube is about 2-1/4".
Length of damper assembly is about 26 1/4 "
Tubes are a little over 23"
Springs are the 20 inch variety.
So am I just getting to be too old to do these things ?